This article explains how to test fiber cable quality using standardized engineering methods for FTTH, ODN, and data center deployments. Fiber optic cable is a type of cabling that contains one or more optical fibers for transmitting data at high speeds and/or over long distances using light. These fibers are most commonly made of glass and are very thin, typically less than a tenth of the width of a human hair. Visual. Related: Fiber Optic Connectors – Identification Guide Regularly testing fiber optic cables helps minimize network downtime, lengthens the network's longevity, reduces maintenance requirements, and helps support network reconfiguration and upgrades. That process, thankfully, is a simple one.